Date registered: Dec 2005
Vehicle: W211 E320 Bluetec R129 SL500 - $1300 car ........ Ford F350 6l
Location: CA Bay Area
Mentioned: 9 Post(s)
Quoted: 1070 Post(s)
I jump stared our different Mercedes on at least 3 occasions and never had any problems. But years ago I "invested" in heavy jump cables with #2 wires and very strong clamps that actually can run the starter on additional battery alone, while the common #10 cables are only good as a helpers. Making sure the clamps are placed on clean connectors helps as well.
On my Ford pickup I was welding dump bed without disconnecting anything. 1999 Ford has less electronics, but week long welding job proved that with ignition off the car computers are safe.